The spike in activity is especially alarming when compared to the 1978-2008 average earthquake rate of only two magnitude 3.0 or larger earthquakes per year.

“While it’s been known for decades that Oklahoma is 'earthquake country' we hope that this new advisory of increased hazard will become a crucial consideration in earthquake preparedness for residents, schools and businesses in the area,” said Dr. Bill Leith, Senior Science Advisor for Earthquakes and Geologic Hazards at USGS, in a statement. “Building owners and government officials should have a special concern for older, unreinforced brick structures, which are vulnerable to serious damage during sufficient shaking.”